Screw anchor foundations and related interfaces for modular, manufactured and prefabricated structures

ABSTRACT

A foundation system for manufactured homes, prefabricated houses, and other structures. Multiple screw anchors are driven into the ground at the desired location of the structure. Preformed grade bars may be placed over the screw anchors to provide a modular foundation without pouring concrete or digging footers. Alternatively, adapters may be attached to one or more of the driven screw anchors to provide a pedestal to receive the grade bar or prefabricated sections of concrete

CROSS REFERENCE TO RELATED APPLICATIONS

This claims priority to provisional patent application No. 62/862,624titled “Universal foundations, precast slabs and related interfaces formodular and prefabricated construction projects,” filed Jun. 17, 2019,the disclosure of which is hereby incorporated by reference in itsentirety.

BACKGROUND

There are many advantages to modular and prefabricated home constructionrelative to building homes onsite. For one, modular and prefabricatedhomes are often built indoors in climate-controlled factories ratherthan exposed to the elements. This keeps the materials dry as well asprotecting them from theft and vandalism. It also avoids weather-relatedconstruction delays. Centralizing construction at one factory simplifiesallows building materials to be delivered to a single location ratherthan to distributed jobsites. In addition, building inside a factoryallows the use of jigs, templates, and computer-controlled machines, allof which result in structures that are built with far greater precisionand consistency relative to ones that are built on-site with hand tools.Still another advantage is that an entire community or even a city maybe constructed off-site, where ever resources are best utilized for thispurpose and then components shipped to locations virtually anywhere inthe world for final assembly.

Modular and/or prefabricated structures do still require some on-sitework, but this work is typically limited to site-preparation includinggrading, laying or running utilities and constructing the foundation.The structures themselves are trucked in, craned on to the foundation,and connected to the utilities and the foundation. The process ofclosing seams and completing utility hook-ups typically takes less thana week. In some cases, even internal fixtures (e.g., plumbing andelectrical) are installed at the factory.

The most time-consuming and labor intensive of onsite activities istypically construction of the foundation. After the site is graded andcompacted, the soil is excavated to make room for the foundation. Insome cases, a continuous trench footer is dug around the entire outlineof the structure. Rebar and wire are placed in the trench then it isfilled with concrete. Anchor bolts are inserted into the drying concreteor drilled and placed after it has set, and the house is built on top ofit the foundation and anchors.

In other cases, the entire footprint of the structure to be built isscraped, leveled, and compacted. Then, concrete is poured over theentire compacted footprint to create a slab on which the home is built.Still further foundations use a combination of these techniques orindividual concrete pads and piers whereby individual piles areexcavated and constructed and piers are built on top of the pile toestablish a uniform building platform. Unfortunately, there is adisconnect between the distributed, inefficient, low-precisiontechniques used to construct foundations and the highly efficient,centralized, precise techniques and process used to build theprefabricated and/or modular structures themselves. This can result inpoor connections between structures and foundations that result inadditional on-site work to conform the foundation and loss of time andmoney. Also, prefabricated structure builders must contract withmultiple regional contractors to construct their foundations rather thansimply shipping foundation components with the rest of the modularand/or prefabricated structure. In recognition of these problems, thepresent disclosure provides foundation systems, components and relatedmethods that greatly simplify the process of laying a foundation forprefabricated and modular building structures and ideally eliminate orat least minimize non-utility-related onsite work.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a conventional strip footing foundation for a buildingstructure;

FIG. 1B is a cross sectional view of the strip footing foundation of 1A;

FIG. 2A is a conventional pile and pier foundation for a buildingstructure;

FIG. 2B is a cross sectional view of the pile and pier foundation of 2A;

FIG. 3A is a truss foundation according to various embodiments of theinvention;

FIG. 3B is a pre-cast slab section for prefabricated and modular homesaccording to various embodiments of the invention;

FIG. 3C is a cross sectional view of the truss interface section of thepre-cast slab and truss foundation according to various embodiments ofthe invention;

FIG. 3D is a top view of the truss interface formed in the pre-cast slabof 3C;

FIG. 3E is a top view of the pan covering the truss interface of 3C;

FIG. 4 is a flow chart detailing steps of a method for installing afoundation such as that shown in FIGS. 3A-E according to variousembodiments of the invention;

FIG. 5 is a perspective view of another pre-cast slab for prefabricatedand modular structures according to various embodiments of theinvention;

FIG. 6A is a pre-cast slab and truss foundation interconnect systemaccording to various embodiments of the invention;

FIG. 6B is a pre-cast slab and monopile foundation interconnect systemaccording to various embodiments of the invention;

FIG. 7A is another pre-cast slab and truss foundation interconnectsystem according to various embodiments of the invention;

FIG. 7B is another pre-cast slab and monopile foundation interconnectsystem according to various embodiments of the invention;

FIG. 8A is an additional pre-cast slab and truss foundation interconnectsystem according to various embodiments of the invention;

FIG. 8B is an additional pre-cast slab and monopile foundationinterconnect system according to various embodiments of the invention;

FIG. 9A is a lift plate for lifting a pre-cast slab according to variousembodiments of the invention;

FIG. 9B is a portion of a pre-cast slab with an integrated lift point;

FIG. 10 is a connector for joining adjacent pre-cast slabs according tovarious embodiments of the invention;

FIGS. 11A and B show components of a grade block foundation according tovarious embodiments of the invention; and

FIG. 12 is a flow chart detailing steps of a method for installing afoundation such as that shown in FIGS. 11A and B according to variousembodiments of the invention.

DESCRIPTION

As discussed above, modular, and prefabricated homes offer manyadvantages over on-site construction. These advantages must be exploitedto address the growing global shortage of quality, affordable homes.However, what is missing from the modular and/or pre-fabricatedconstruction paradigm in a universal foundation that allows thestructure to quickly and accurately secured to the building siteregardless of soil type, without needing to excavate and pour a customconcrete foundation. Preferably such a foundation can be manufacturedcentrally and shipped with the other building components or at leastdelivered to the jobsite ready to be assembled ahead of the remainingmodular and/or prefabricated components. To that end, the applicant ofthis disclosure has developed an A-frame-shaped truss foundation that isparticularly well-suited to this application. The system is knowncommercially as EARTH TRUSS. The EARTH TRUSS system consists of a pairof screw anchors that are rotated into supporting ground at angles toone another and extended with above-ground upper legs that are joinedwith an adapter to form a unitary A-frame-shaped truss structure.

EARTH TRUSS was originally developed to support single-axis solartrackers. When wind strikes a tracker array, large lateral loads must beresisted by the foundation. With monopiles, these loads impart a bendingmoment onto the foundation components. By using A-frame-shaped trussesrather than monopiles, these lateral loads are instead translated intotension and compression in the legs. Because individual structuralmembers are relatively good at resist axial loads, as opposed toresisting bending, less steel may be used to support the same sizetracker.

The EARTH TRUSS relies on a specialized machine or attachment for ageneral-purpose machine that uses a combination of downward force androtation to drive screw anchors into the earth. These components andmachines are easily adapted to construct robust foundations for supportother structures, including modular and prefabricated homes. They can beconfigured as a two-legged truss as with single-axis trackerfoundations, or even as plumb piles depending on site conditions andsheering concerns. The present disclosure focuses on building systemsand related methods that combine EARTH TRUSS components with pre-castconcrete slab sections to form fast, accurate, robust, and water-proofpre-fabricated foundations that can be constructed very quickly, shippedto the homesite as a kit, and assembled with minimal site preparation.

To that end, the present invention will now be described in the contextof the drawing figures where like structures are referred to with likedesignations. FIGS. 1A and B show conventional strip footing foundation10. Foundation 10 is constructed by excavating a trench around theperimeter of the intended structure (i.e., home, office, modularclassroom, etc.), placing rebar, wireframe forms, and/or otherreinforcing structures into the trench, and pouring concrete over them.Then concrete blocks are used to make above-ground foundation 14 onpoured concrete footer 12. Gravel 11 may also be poured inside the wallsof foundation 14 and a concrete slab poured on top of the gravel tocreate a slab such as slab 13. Anchors, ties, or other structures 15 aretypically inserted into concrete block foundation 14 before it sets toprovide attachment points for the rest of the structure. In the case ofa modular or premanufactured homes, these anchors will serve as thepoints of attachment. Otherwise, if the house is built on-site, theseanchors are received within wooden beams and/or floor joists, and thehome is built up from there.

FIGS. 2A and B show another conventional foundation 20 consisting ofpiers 24 and piles 22. In such a foundation, individual pile portions 22are excavated at strategic points around a site to support load bearingportions of the structure in accordance with a construction plan. A woodor cardboard form may be placed around the excavated opening and wire,rebar or other structural components placed inside before filling itwith liquid concrete. After pile 22 has set, concrete, wooden or steelpiers 24 are constructed on top to form a level, elevated mountingsurface on which to set or construct the home. Piers 24 may have capportion 26 with integral anchor 28 that serves as the mechanicalinterface between the home and foundation 20.

Though first developed hundreds if not thousands of years ago, prior artfoundations 10, 20 shown in FIGS. 1A/B and 2A/B continue to be usedtoday. They require substantial onsite work with local components andlabor that is completely disconnected from the manufacturing process ofthe modular or prefabricated structure that will be set on it other thanknowing the necessary foundation dimensions. As a result, even ifanchors 14/28 are positioned perfectly, something that rarely occurs,the foundation will be the least efficient or cost-effective portion ofthe project. Across a builder's or manufacturer's portfolio ofdevelopment projects there will be varying quality and varying expensedepending on many local conditions (e.g., labor rates, materialavailability, weather, etc.). To overcome these problems, the Applicantof this disclosure has proposed a system that allows foundationcomponents to be centrally manufactured and shipped as a kit to the jobsite for rapid assembly. They may be shipped with other modular and/orprefabricated components or shipped separately beforehand, so that theentire structure, including the foundation, can be assembled on-sitewithout pouring concrete, extensive site preparation, or excavation.FIGS. 3A and 3B show the components of this novel foundation systemaccording to various exemplary embodiments of the invention.

FIG. 3A shows exemplary truss foundation 50 according to variousembodiments of the invention. Exemplary truss foundation 50 shown hereconsists of a pair of screw anchors 52 driven into the ground adjacentone another and in a substantially common plane. When used to supportsingle-axis trackers, this plane is typically oriented East to West,however, for supporting modular and prefabricated homes, they may beoriented to match the orientation of the outer walls of the structure,that is, with some trusses oriented orthogonally or at 90-degreesrelative to other foundations to insure that any shearing forces aretranslated into tension and compression as necessary. In variousembodiments, and as shown, screw anchors 52 are driven until they arealmost completely embedded into the ground.

As shown, screw anchors 52 are elongated metal tubes that may span oneto two meters with a sub-100 mm outside diameter. External threads 53are located at the lower end of each anchor 52 and driving couplers 54are attached at the opposing upper end. Driving couplers 54 may beengaged by the chuck of a rotary driver to transfer torque and downforceto screw anchors 52 to drive them into the ground. Couplers 54 may alsoprovide a mechanism for joining upper legs 55 to the end of each screwanchor 52 after the screw anchor is driven. Upper leg sections 55 aresleeved over respective ones of driving couplers 54 to extend the axisof each screw anchor 52 above ground. It should be appreciated thatdepending on the required height above grade, screw anchors 52 may beused alone, that is, without needing upper legs 52. Then, an adapter ortruss cap, such as adapter 60, is used to join each upper leg 55 (orscrew anchor 52) to form a unitary A-frame-shaped truss foundation 50.In various embodiments and as shown, adapter 60 provides support surface62 and may include pedestal 64, with threaded anchor bolt opening, ananchor protecting out of pedestal 64, or other structure to mechanicallycouple adapter 60, and by extension, foundation 50 to the structure itwill support.

FIG. 3B shows pre-cast slab section 100 that makes up part of thefoundation as well as the subfloor or base of the prefabricatedstructure according to various embodiments of the invention. In someembodiments, modular and prefabricated building components may be setdirectly on top of slab 100. In other embodiments, finished surfaces(e.g., radiant heat, tile, hardwood, etc.) may be installed directly ontop of the pre-cast slab without needing floor trusses or a sub-floor.In various embodiments, pre-cast slab 100 is formed in regular modularshapes (e.g., 10-feet×20-feet rectangles) that can be interconnected incommon or adjacent planes to form larger structures. In otherembodiments, they may be formed in custom shapes to accommodate thefootprint of the structure. In various embodiments, pre-cast slabs areconstructed by pouring concrete into a form that has the correct outerdimensions, is filled with re-bar and/or wire, and that has protrusionsthat create through-holes or voids 108, 110, 130 at desired locationsfor the foundation interface, utility connections and/or lift points. Insome embodiments, conventional concrete mixes may be used. Others mayrequire stronger and/or more flexible formulations to accommodate theforces of cable-based post-tensioning.

In the example of 3B, a series of through holes 110 have been formed inpre-cast slab 100 at points where it will be supported by thefoundations, such as, for example, foundation 50 shown in 3A. Utilitythrough-holes 130 may be separate formed in the center of each slap 100,or elsewhere, to allow utility hookups (e.g., water, sewer, electricity,natural gas, etc. to pass through). Smaller though-holes such as holes108 may be used as lift points to enable pre-cast sections 100 to becraned down onto an array of foundations. Perimeter cutouts 105 may beformed around the outside of each slab 100 at various points. Suchcutouts 105 may be used to join one slab to an adjacent one. Cutouts 105may be also be used as lift points, obviating the need for separateholes 108. One or several of through-holes 105, 110, 130, may bereinforced with metal or preformed metal shapes that create voids aswell as integral reinforced steel interface sections for mechanicallyinterfacing the slab to the truss foundations or other structures. Theseshapes may be moved around within the mold before being locked intoplace and numbered to specifically match the foundation requirements ofthe particular site.

When manufacturing slab 100, a layer of PRECON or other suitablematerial may be laid down within the form used to make pre-cast section100 to create a water barrier on the underside as well as up into theutility knockouts and foundation interface openings and lift pointsbefore the concrete is poured. PRECON is a composite sheet membranemanufactured and sold by W.R. Meadows of Hampshire, Ill. that forms amechanical bond to poured concrete as the concrete cures. It should beappreciated that other products from other manufacturers that performssimilarly may also be used. Once the concrete has set, these pre-castsections can be loaded onto truck, train or into a shipping containerwith the truss members and can travel as a kit to the homesite beassembled.

Turning now to FIG. 3C, this figure shows cross section detail of onethrough-hole 110 for interfacing slap 100 with foundation 50 accordingto various embodiments of the invention. In this example, hole 110consists of metal reinforced sidewalls 113 resting against walls 112.Metal reinforced sidewalls 113 may consist of a box that sits in themold used to create slab 100. In the cross-sectional view of 3C, walls112 and box 113 define a two-sided ledge that houses slidable transferbar 114. In various embodiments, transfer bar 114 fits within theextended sides 112 to allow the bar to slide along the ledge in onedirection (X or Y) in-plane (without movement in the Z-direction). Thiswill enable bar 114 to be easily moved to compensate for any in-planemisalignment between the foundation through-hole 110 and adapter 60.FIG. 3D provides an overhead view of opening 110. As shown, transfer bar114 may preferably have one or more long slots 115 formed in it tocompensate for misalignment in the other planar direction orthogonal tothe sliding direction of the bar. Slot 115 in transfer bar 114 as thebar's ability to move back in forth within the metal reinforced opening113 allow compensation for up to several inches of misalignment in twodirection between through-hole 110 and adapter 60 without any impact tothe integrity of the connection. This will prevent foundationmisalignment from propagating through the building supported by slab100. It should be appreciated that although not shown in FIG. 3B, slab100 may also have a series of anchors around its perimeter that projectabove the surface of slab 100 for connecting to the prefabricated home,modular home or other structure lowered and/or built on top of it. Suchanchors can be easily placed within the mold prior to pouring theconcrete so that they are correctly located.

With continued reference to FIG. 3C, anchor bolt 116 projects up throughtransfer bar 114 via slot 115. In various embodiments, a pan such as pan120 is placed in through-hole 110 above bar 114. A nut such as nut 118is used to secure pan 110 to adapter 60 via bolt 116. It should beappreciated that in various embodiments, bolt 116 may pass down fromabove pan 120 into adapter 60 through slot 115 in transfer bar 114. Invarious embodiments, after pan 120 is secured, a layer of PRECON 122 orother suitable material may be placed in pan 120 before filling it withconcrete 124, bentonite or other suitable filler to create a water proofseal.

FIG. 3D shows a portion of hole 110 looking down from above withtransfer bar 114 and slot 115 visible from above. This view isconsistent with the view after slab 100 has been lowered onto thefoundation. Similarly, 3E shows the same view after pan 120 has beendropped into hole 110. As seen, pan 100 has a relatively large openingin its bottom to permit access to the bar at different positions.

Turning now to FIG. 4, this figure is a flow chart detailing steps ofmethod 160 for installing a foundation such as that shown in FIGS. 3A-Eaccording to various embodiments of the invention. In variousembodiments, installation begins in step 162 by installing multiplescrew anchors into the ground at the intended building site. In variousembodiments, this is done in accordance with a plan matched to themanufacturing of the pre-cast slab(s) so that they foundation pedestalswill match up with corresponding openings in the slab. In variousembodiments, this may be accomplished by unrolling a mat or othertemplate that has the anchor locations marked on it. The mat may alsoserve a vapor barrier and/or insect barrier and may be staked into theground or otherwise attached. As discussed in greater detail herein, thescrew anchors may be installed in adjacent pairs, angled towards oneanother to form the base of an A-frame-shaped truss foundation, or inother embodiments shown herein, as plumb monopiles.

Once the screw anchors have been driven, then, in step 164, apexhardware is installed. If necessary, this may include joining upper legsto their respective screw anchors, depending on the amount ofabove-ground elevation required for the particular site. If the screwanchors are installed in adjacent pairs, adapters are used to join thefree end of each adjacent upper leg pair. Alternatively, if the screwanchors are driven as plumb monopiles, an upper leg is joined to eachscrew anchor, if necessary, and an adapter is joined to the upper end ofthe upper leg. In either case, in various embodiments, each adapter willinclude some leveling adjustment so that the adapters can be adjusted tobe level to each other before being locked into place relative to thelegs and/or anchors. In various embodiments, and as discussed and shownherein, the adapters may include a pedestal, anchor, or other mechanicalfeatures to mate with and secure the pre-cast slab. Then, in step 166, acrane is used to place one or more pre-cast slab sections on top of thepedestals and/or adapters in accordance with the plan. Manualmanipulation of the transfer bars may be performed as the slab islowered to allow them to be properly aligned with their respectivepedestals as the pre-cast slab is being lowered. This may beaccomplished by simply sliding. Alternatively, a tool may turn a cam orgear that causes the transfer bar to slide in-plane. In variousembodiments, the adapter may have an anchor bolt or other fastenerprojecting above it that engages a slot or opening in the transfer bar.Once alignment with the respective anchors has been achieved, the entireslab may be lowered to completely rest on the supported transfer barswhich, in turn, are resting on the foundation via the adapter andpedestal (see, e.g., FIG. 3C).

In various embodiments, placement of the pre-cast slab sections on thetruss or monopile foundations may open up a space between the bottomside of the transfer bars and the walls of the steel reinforcement inthe truss interface openings. In various embodiments, in step 168, theprocess is completed by securing the slab and sealing the through-holes.In various embodiments, to accomplish this an installer may reach fromthe top side of the slab to place a plug of bentonite clay in the gapbetween the transfer bar and the walls to prevent water from flowingpast the transfer bar. Bentonite clay may be particular useful in thisapplication because it remains pliable over long periods of time withoutlosing its cohesion. It should be appreciated, however, that othermaterials may also be used in place or in addition to bentonite clay.For example, foam sheets or other suitable material may be placed on theledges below the transfer bar since these lower ledges are not loadbearing. Once the gap has been sealed, a pan may be dropped in eachtruss interface opening. The pan may have a large cutout in its bottomto account for the different positions of the transfer bar and anchor.Also, a large retaining nut may thread onto the anchor either before orafter the pan is set. The nut will prevent uplift and secure the slab tothe individual trusses. In various embodiments, the pan may be linedwith a sheet of PRECON or other suitable material. In variousembodiments, the anchor will be pressed through the layer of PRECON oran opening will be cut in it to allow the bolt to pass through. Then, anon-shrinking grout or other suitable material may be deposited in thepan. In various embodiments, this will make the truss interfacewatertight and prevent water and/or moisture from passing through theinterface and contacting structures or components above.

It should be appreciated that in various embodiments, the pan may beomitted, and the concrete or non-shrinking grout may be poured directlyon a layer of PRECON in the interface opening. In sites where wateringress is not a concern, this step may be omitted or replaced with apest barrier to prevent bugs, termites, and/or rodents from passingthrough the foundation. Also, as shown in the FIG. 3C, the anchor boltis shown as a static member that projects above the adapter. It shouldbe appreciated that the anchor bolt may have a hexagonal or star-shapedopening in its top surface that can receive a tool to allow rotation ofthe bolt. In various embodiments, rotation may elevate or lower thepedestal relative to the adapter and provide a mechanism formicro-leveling the pre-cast slab after its set or to leveling thepedestal relative to surrounding pedestals before the pre-cast slab isset.

Turning now to FIG. 5, this figure shows pre-cast slab 200 according tovarious other embodiments of the invention. Instead of the large trussinterface opening in the slab of FIGS. 3B/C, such as openings 110 inslab 100, foundation interface openings 210 in the slab 200 shown inFIG. 5 are formed recessed and specifically shaped to match the geometryof the pedestals supported by each foundation. In this example, thegeometry of each opening is a tapered cuboid but it should beappreciated that other shapes, including pyramids, posts, cuboids,cones, etc. may be used instead. Like slab 100 shown in FIGS. 3B/C, slab200 also includes utility knock outs or openings 230 and several liftpoint openings 208. Lift point openings 208 could contain a reinforcedmetal lining and bar, as shown for example, in FIG. 9B or,alternatively, could simply be openings that receive a removable liftplate such as lift plate 405 as shown in 9A. Also, like slab 100 ofFIGS. 3B/C slab 200 of FIG. 5 includes several coupling joints 205around its perimeter, which in the example, are shown as semi-circularopenings with a metal bar across them. These may be used to joinadjacent slabs to form a larger slab structure, such as, for example,with a connector such connector 425 shown in FIG. 10. In that case,flanges 426 will fit between the wall of the opening and the bar ofadjacent slabs 200 locking them together. Alternatively, or in addition,these joints may be used to hang trim pieces, pipes, conduit, or otherstructures, to run communication lines, or for any other purpose. Byhaving the foundation set back relative to the outer edge of each slab200, trim pieces may be hung flush with the outer wall via joints 205.As with pre-cast slab 100 of FIGS. 3B/C, slab 200 may also be formedwith a layer of PRECON attached to its underside that extends around thesides and up into all the through-holes (e.g., lift points 208, utilityknockouts 230, and truss interface openings 210).

The remaining figures and corresponding discussion show interfaces thatmay be used to join pre-cast members to truss foundations or monopilescrew anchors according to various exemplary embodiments of theinvention. Starting with FIG. 6A, this figure shows a portion ofpre-cast slab 200 of FIG. 5 with truss foundation 70 below it. Trussfoundation 70 shown here consists of a pair of legs extending below andabove ground that are angled towards one another and joined with adapter74. In this example, support plate 77 sits on top surface 75 of theadapter 74. Support plate 77 may have a pair of holes 78 or othersuitable features to enable it to be securely attached to adapter 74.Plate 77 may also have integral pedestal 79 formed on top surface. Invarious embodiments, pedestal 79 is attached to the plate so that it canmove or pivot around the surface of the plate at different positions toenable it to be matched to the position of the corresponding void in theinterface opening of the slab to compensate for any misalignment whenplacing slab 200. Alternatively, interface opening 210 may also be ableto rotate or slide in-plane in a manner similar to the transfer barshown in 3C so that each opening may be positioned to be directly aboveat and at the correct rotational orientation to receive one of thepedestals. For example, as shown in the cutaway view of 6A, theinterface opening 210 may actually be constructed of a plate capturedwithin the opening that can slide in X and Y directions and/or rotatein-plane to enable it to be oriented precisely so that opening 211 isdirectly above pedestal 79.

In the example of 6A, washer 212 sits above interface opening 210 afterslab 200 has been lowered on to pedestals 79 to create a flat surface.An anchor bolt such as bolt 213 may pass down from above through washer212 and into a threaded opening in the top surface of pedestal 79.Alternatively, pedestal 79 may contain an anchor protruding up above it.In such embodiments, anchor bolt 213 shown in 6A will be replaced with aretaining nut. Such modifications are within the spirit and scope of theinvention. Though not shown, after slab 200 has been secured with theanchor bolt or other fastener, opening 210 containing the bolt andwasher may be filled with non-shrinking grout or other suitable materialto create a uniform, water resistant upper surface to slab 200.

FIG. 6B shows a slab and foundation interface like that of 5A but thetruss foundation 70 has been replaced with a single, plumb-orientedmonopile foundation 80. In various embodiments, monopile foundation 80consists of a single screw anchor 82 driven substantially plumb into thesupporting ground with an upper leg attached thereto, if necessary.Then, adapter 84, similar to adapter 74 shown in 6A is set on top ofanchor or leg 82 and the remaining connections occur in the same manneras in the context of 6A with the same modifications possible.

Turning now to FIGS. 7A and B, these figures show another exemplaryinterface between pre-cast slab 200 and screw anchor foundationsaccording to various embodiments of the invention. Pre-cast slab portion200 is substantially the same as that shown in FIGS. 6A and B with thesame modifications possible. The differences lie in the adapter andpedestal used to support it. In the example of FIG. 7A, adapters 93 hasa cross shape with four anchor bolts 96 protruding upward towards slab200. Support plate 240 is attached to adapter 93 so that anchor bolts 96pass through and are secured with corresponding nuts (not shown).Pedestal 244 is formed on or attached to support plate 240 with atapered cuboid shape. In various embodiments, cuboid pedestal 244 may berotatable about a pivot point around the surface of plate 240 in-planeto enable pedestal 240 to be aligned with the corresponding cuboidopening 231. Alternatively, foundation interface opening 210 in therecess of slab 200 may include plate 230 that is trapped within the slabbut able to rotate and/or move in the X and Y directions in-plane(without changing in the Z-direction) to ensure fitment between pedestal244 and its corresponding opening 231. In various embodiments, washer212 under anchor bolt 213 may be dimensioned small enough to enable itto move around within recess 210 to account for adjustment between eachpedestal 244 and its corresponding opening 231.

FIG. 7B shows substantially the same interface as 7A except that trussfoundation 90 has again been replaced with a plumb monopile foundationconsist of single screw anchor driven 92 at a substantially plumborientation. If necessary, an upper leg (not shown) may be attached tothe above-ground end of screw anchor 92. Pre-cast slab 200 and itsinterface components are otherwise identical to that shown in 7A.

Turning now to FIGS. 8A and B, these figures show yet another simplifiedinterface between pre-cast slab section 300 and foundations 130, 140respectively according to various embodiments of the invention. Startingwith 8A, the interface shown here consists of adapter 135 with singleanchor bolt 138 projecting upward from its upper surface 137. In thisexemplary embodiment, anchor bolt 138 is received within interfaceopening 312 of recess 310 as slab 300 sits on adapter 135. Large washer315 fits over anchor bolt 138 and retaining nut 318 is attached to thehead of anchor bolt 318. Though not shown in this exemplary figure, aplate or other force spreading structure may sit atop adapter 135 todistribute the weight of pre-cast slab 300 over a larger surface area.Also, as discussed herein, anchor bolt 138 may have a hexagonal,star-shaped or other shaped opening at its head so that inserting a toolinto that opening and rotating it will elevate top portion 137 ofadapter 135 contacting the slab to raise (or lower) the level of theslab at that interface. This may be performed before, while, or afterplacing slab 300 on adapter 135. In various embodiments, opening 312will be much larger than the diameter of anchor bolt 138 to compensatefor any misalignment between bolt 138 and opening 312. Also, the size ofrecess 310 around opening 312 relative to the size of washer 315 willallow retaining nut 318 to be attached at multiple different X-Ylocations without comprising the integrity of the connection. FIG. 8Bshows a similar interface as 8A but truss foundation 130 has again beenreplaced with a single, plumb monopile foundation 140. The componentsabove adapter 145 are substantially the same as that shown and discussedin the context of FIG. 8A.

Turning now to FIGS. 11A and B, these figures show yet anotherfoundation system according to various other embodiments of theinvention. The components of system 450 include grade bar sections 460and screw anchor members 470. Grade bar sections 460 may be formed fromconcrete, reinforced concrete or other aggregate solution that is pouredinto a mold and hardened. In various embodiments, the sections areuniversal. In other embodiments, they may be formed to specificdimension and numbered or otherwise marked with indicia matching tofoundation plan for the structure. Each section 460 may include on morethrough-holes that enable them to be securely connected to one anotherand to top end 474 of anchors 470. In various embodiments, and as shownin 11A, transition portion 466 of the bar may have a curved surface toenable the next adjacent section 460 to be oriented at an angle relativeto that one so long as openings 464 on surface 462 line up.

In various embodiments, bolt or fastener passes through washer 472 intoopening 464 is received in threaded opening 476 in head portion 474 ofscrew anchor 470. The bottom side of section 460 will rest on supportsurface 475 to maintain level. In various embodiments, head portion 474may be rotatable with a socket type tool to raise or lower head portion474 including support 475 to adjust the level of section 460 after ithas been placed on screw anchor 470. Also, as seen in 11B, afteradjacent sections have been joined via bolt 470 to other means, ananchor such as anchor 482 may be inserted above bolt 470 in hole 464 andthen remainder of the hole filled with grout 482 or other suitablematerial. In various embodiments, opening 464 will be large enough toenable anchor bolt 480 to be moved around to the proper orientation tomate with the remainder of the structure to be placed on or built abovegrade bars 460.

In various embodiments, grade bar sections 460 will be designed based onthe specific plans for the structure to be erected so that anchor boltsare located at the desired locations. Also, it should be appreciatedthat adjacent sections of grade bar may be joined directly, that is, notvia the ground penetrating screw anchor. In other words, each grade barsections may be placed on top of one or more screw anchors but theconnection between adjacent sections may be made with hardware that onlypenetrate the two overlapping sections and does not extend down into thesupporting ground below.

FIG. 12 is a flow chart detailing the steps of a method for installing afoundation system such as that shown in FIGS. 11A and B. Method 500begins in step 505 where the various anchors used to make up thefoundation are installed. As discussed herein, this may compriserotating them into the ground with a rotary driver using a combinationof downforce and torque at precise locations indicated in the foundationplan. The anchors may extend around the perimeter of the structure only,or alternatively may also intermittently pass through the middleconnecting sections of the perimeter, as necessary. In variousembodiments, anchors are driven at a plumb orientation or orthogonal tothe desired placement of the grade bars so that the height of the topend of each anchor is very consistent relative to other anchors in thesame foundation.

Next, in step 510, after all the screw anchors have been consistentdriven in accordance with the foundation plan, the grade bars are laiddown above the anchors. In various embodiments, this is accomplished byhoisting each grade bar section with a crane and lowering is so that atleast one opening formed in the bar aligns with the head a correspondingone of the screw anchors. The bar is lowered until it rests on thesupport portion in the head of the screw anchor. As discussed in thecontext of FIGS. 11A and B, it may be possible to rotate the head of theanchor with tool to raise or lower the support portion, thereby raisingor lowering the grade bar to be level. This process may be repeateduntil each grade bar making up the foundation has been placed on thescrew anchors.

Next, in step 515, each bar is secured to its adjacent bar. As discussedabove, in some embodiments, screw anchors may pass through the gradebars at the overlap joint between each bar, obviating the need for thisstep. In other embodiments, however, separate hardware may be passedthrough the overlapping portions of each adjacent bar to lock themtogether. Then, each opening passing through the bars, whether to jointwo adjacent bars, connect the bars to their respective screw anchors,or both, are filled with grout or other suitable material to seal them.Joint between adjacent bars may also be grouted and/or insulated toprevent ingress of water, air, and insects. Then, the process iscompleted in step 520 by placing anchor bolts or other tie-in structuresin the grouted openings to support the structure that will be set on orbuilt above the foundation.

The various foundations and pre-cast slabs shown herein will provide amodular, transportable, precise, and easily installed system that willrapidly increase the deployment of modular and prefabricates homes andother structures. They will also provide a uniform and predictablefoundation that can very accurately and consistently predict foundationcosts on a per square foot basis regardless of site conditions and withminimal pre-constructions site preparation.

The embodiments of the present inventions are not to be limited in scopeby the specific embodiments described herein. Indeed, variousmodifications of the embodiments of the present inventions, in additionto those described herein, will be apparent to those of ordinary skillin the art from the foregoing description and accompanying drawings.Thus, such modifications are intended to fall within the scope of thefollowing appended claims. Further, although some of the embodiments ofthe present invention have been described herein in the context of aparticular implementation in a particular environment for a particularpurpose, those of ordinary skill in the art will recognize that itsusefulness is not limited thereto and that the embodiments of thepresent inventions can be beneficially implemented in any number ofenvironments for any number of purposes. Accordingly, the claims setforth below should be construed in view of the full breath and spirit ofthe embodiments of the present inventions as disclosed herein.

1. A foundation system comprising: a first plurality of screw anchors; and a second plurality of grade bar sections, each grade bar section comprising an elongated concrete structure adapted at each end to overlap with an adjacent grade bar section and to be supported from below by at least one of the first plurality of screw anchors.
 2. The foundation system according to claim 1, wherein each screw anchor comprises a head portion that is received in an opening formed in one of the grade bar sections.
 3. The foundation system according to claim 2, wherein a lower end of the head portion terminates in a support having a diameter wider than the opening.
 4. The foundation system according to claim 3, wherein the head portion is rotatable relative to the screw anchor portion to raise and lower the support relative to the screw anchor after the grade bar portion has been lowered over the head portion.
 5. The foundation system according to claim 1, further comprising a fastener passing through a portion of each overlapping grade bar section to join them together.
 6. The foundation system according to claim 5, further comprising at least one anchor bolt extending above at least one of the grade bar sections.
 7. A foundation system comprising: at least one screw anchor; and at least one pre-cast concrete section that is supported by the at least one screw anchor at a pre-formed through-hole formed in the pre-cast concrete section.
 8. The foundation system according to claim 7, further comprising an adapter attached to an above-ground end of the at least one screw anchor for supporting the pre-cast concrete section at the pre-formed through-hole.
 9. The foundation system according to claim 8, further comprising an anchor bolt for joining the adapter to the pre-cast concrete section via the through-hole.
 10. The foundation system according to claim 7, wherein the pre-cast concrete section is a pre-cast concrete slab.
 11. The foundation system according to claim 7, wherein the pre-cast concrete section is a pre-cast grade bar.
 12. The foundation system according to claim 7, wherein the at least one screw anchor comprises an elongated hollow shaft with a thread form at one end and head portion at an opposing end.
 13. The foundation system according to claim 12, wherein the head portion terminates at a lower end in a support having a diameter larger than the pre-formed through-hole.
 14. The foundation system according to claim 12, wherein rotation of the head portion through the pre-cast concrete section moves the head portion and the pre-cast concrete section relative to the elongated hollow shaft.
 15. A method of forming a foundation for a structure comprising: driving at least one screw anchor into supporting ground on a foundation site; and placing a pre-cast concrete section above the at least one screw anchor so that it is supported by the at least one screw anchor.
 16. The method according to claim 15, wherein driving the at least one screw anchor comprises driving the at least one screw anchor at a predetermined position to support portion of a pre-cast concrete slab.
 17. The method according to claim 16, wherein placing the pre-cast concrete section above the at least one screw anchor comprises placing the pre-cast concrete slab on an adapter connected to the at least one screw anchor so that the adapter is aligned with a through-hole formed in the slab.
 18. The method according to claim 15, wherein driving the at least one screw anchor comprises driving at least one screw anchor at a predetermined position to support a portion of a pre-cast grade bar foundation section.
 19. The method according to claim 18, wherein placing the pre-cast concrete section above the at least one screw anchor comprises placing the pre-cast grade bar section on the at least one screw anchor so that a head of the least one screw anchor is received in opening formed in the pre-cast grade bar section. 